Copenhagen, Denmark — Hopes for a Copenhagen global warming pact rose yesterday when the US and China appeared to move closer on two points: the issue of long-term climate aid for poor countries, and the need to look over other countries’ shoulders to ensure they are meeting their commitments.

But overnight, negotiations took a turn for the worse. This morning, when President Obama arrived to give a speech, he first went into informal negotiations with government leaders from 19 countries, including developing nations such as China, India, Ethiopia, and Bangladesh.

In addition, he had one-on-one talks for nearly an hour with China’s Premier Wen Jiabao. The talks “made progress,” according to a White House official. After his speech, he met with 12 heads of state at a formal luncheon sponsored by the Danish government.

One sticking point: legally binding agreement, or political deal?

Among the sticking points: Several countries that are party to the 1997 Kyoto Protocol want the US to take on legally binding emissions commitments in any new agreement, or they will balk at getting tougher on their emissions in a second commitment period under the protocol.

The US is not party to the agreement, but instead is negotiating over provisions to a second agreement that would bring it and developing countries into a global climate pact. The tiff highlights an overlap between what are typically seen as separate negotiating tracks.

For its part, the US has suggested it would be willing to be bound to its targets – assuming Congress passes energy and climate legislation that the targets are based on – as long as China is, too. While China is happy to have the US agree to binding targets internationally, it so far has refused to do the same.

Small-island nations, some of which are literally vanishing beneath rising sea levels, insist that any agreement coming out of Copenhagen be legally binding, rather than the political agreement many developed countries see as likely.

Heads of state involved at a nitty-gritty level usually left to 'sherpas'

These are among the issues countries were wrangling over into the wee hours of the morning. Heads of state were engaged in negotiations at a level of detail usually left to their “sherpas.”

The talks could well lead to a general political statement, with some kind of pledge to resolve remaining issues by next December’s climate talks in Mexico City.